Increase cost compared to what? You can't compare it to current rental systems, you have to compare it to Blu-ray etc. If the cost of buying a digital copy is s

Increase cost compared to what? You can't compare it to current rental systems, you have to compare it to Blu-ray etc. If the cost of buying a digital copy is significantly higher than Blu-ray then people will just stick with Blu-ray. If they don't want to issue such deals at all then that's fine too, but they just can't use the words "buy" or "purchase" at all and can only say "rent".